I haven't played any game of God of War but saw a video were Fenrir (Fenrisúlfr) appeared as a cute friendly puppy. I liked it.
Haven't seen more scenes than that, but I know that the stoopid motherfucker of Kratos haven't even tried to touch the wolve because everybody knows that Fenrir would destroy Kratos ass in a fight, there is no possibility for anyone to beat Fenrisúlfr, that includes Viðarr son of Odin, he is not treat for the wolf.
Anyone would shit his pants in front of Vánagandr and his sons Hati and Skoll, the most majestic and powerful wolves I have seen in mythology so far.
As ancient words said (referring to Fenrir):
''The wolf will come. And the world will burn. The wolf will devour the moon. He'll devour the sun. He'll devour everything."
There is no chance for anyone in mythology to beat Vánagandr, Kratos and Viðarr are nothing in front of Fenrisúlfr.